Improve MPG by 10% without costly engine development

Waste heat recovery can delivery a step change in efficiency. 60% of fuel is turned directly into heat before any useful work is done.

When calculating efficiency it is necessary to consider the useful work done compared to the total energy released. The graphic below is copied from the US Department of Energy website at and shows the distribution of energy usage for a typical car.

Energy usage in a typical car

Thermal losses at the engine are given as between 60% and 64% for an urban driving cycle. This represents the energy lost as heat at the engine before any useful work is done. If we work with a figure of 60% this leaves 40% of the energy in the fuel that was originally burned. Of this remaining 40% around half of it is converted to useful work done at the wheels.

Parasitic losses (such as the alternator, water pump, power steering pump, etc) account for 5% of the total energy in the burned fuel. Automobile ancillary equipment is becoming increasingly driven by electricity and therefore the alternator accounts for a significant (and increasing) proportion of the parasitic loss.

Aptovis heat recovery products are designed to replace the alternator in a car, generating the required electricity from waste heat in the exhaust. It is possible to improve a typical cars fuel consumption by a staggering 10% by using this technique. As the US Department of Energy says, “the potential to improve fuel efficiency with advanced technologies is enormous” –

The keys to success in this application are low costs, high power density and reliability. Aptovis ARC products have been designed for high volume applications where extended operation is required with minimal maintenance.